An internally resisted coil doesn't need a ballast.
A stock style Mopar canister coil does, or it will get hot.
For a run stand I would probably opt for a C or E core coil like the newer trucks have.
It doesn't need a ballast, is small, puts out a great spark, is easy to wire up and isn't oil filled or cooled.
Just curious, have you ever run a coil like the one pictured on a older car? I guess I never thought about putting one of those on. I think getting a coil wire that has two different ends (coil/cap) would be difficult.
